Reader is very slow.
There is a bug in 5.1.6 that makes reader print out debug messages for every commit.
1. Turn on SP_ORD_DEBUG_FLAG 0x01040800 (for slow reader)
2. There is a bug in 5.1.6 that makes reader print out debug messages for every commit. If the log shows that unconditional debug printing out COMMITs, etc, the workaround is to set SP_ORD_DEBUG_OBJECT to 1. This essentially prevents the debug messages regarding commits from printing out since the default of 0 matches the object_id's in the commits (0):
sp_ctrl>set param SP_ORD_DEBUG_OBJECT 1
NOTE: You don't need to rebounce reader because this is a live parameter.
3. Also check if you mount the filesystem for the PROD_DIR and VAR_DIR directories with an option called mincache=direct, if yes, then try to mount without option and monitor the result.